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JJB

Weird rattle...

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Hello folks, 

I recently posted a video about some issues I've been having with my GT86 - 

 

In that video I speak of a rattle that I've had for a good month or so now, it seems to happen around the 3000-3500 rpm mark, or rather when the vibration from the engine is a little higher than usual - it sounds like a part vibrating on metal, from the left underside of the car. I imagine it to be something like the exhaust vibrating on something and I originally thought it to be a nut vibrating somewhat, people have mentioned the rattles you get in the GT86, I have them too but this is a little different.  It seems to happen more so when the car is cold, but it does happen when it's warm too just not as often (it could be just as often but my music drowning it out)

I spoke with the chap who's helped fit a fair few of my parts and he recommended to smack the backbox a little bit in case a baffle had worked its way loose, but given it's under the left hand side of the car I wouldn't be surprised if it was exhaust related (stock exhaust atm).

Other people have cited it could be a mount, or a hanger for the exhaust. 

Anyone had this issue before or something similar, any ideas as to what it could be?

Thanks in advance folks

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Hello folks, 
I recently posted a video about some issues I've been having with my GT86 - 
 
In that video I speak of a rattle that I've had for a good month or so now, it seems to happen around the 3000-3500 rpm mark, or rather when the vibration from the engine is a little higher than usual - it sounds like a part vibrating on metal, from the left underside of the car. I imagine it to be something like the exhaust vibrating on something and I originally thought it to be a nut vibrating somewhat, people have mentioned the rattles you get in the GT86, I have them too but this is a little different.  It seems to happen more so when the car is cold, but it does happen when it's warm too just not as often (it could be just as often but my music drowning it out)
I spoke with the chap who's helped fit a fair few of my parts and he recommended to smack the backbox a little bit in case a baffle had worked its way loose, but given it's under the left hand side of the car I wouldn't be surprised if it was exhaust related (stock exhaust atm).
Other people have cited it could be a mount, or a hanger for the exhaust. 
Anyone had this issue before or something similar, any ideas as to what it could be?
Thanks in advance folks
Engine undertray maybe

Sent from my COL-L29 using Tapatalk

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If it's aftermarket manifold, I'd say checking the clearance between it and the undertray should be your first port of call, definitely. 

I have the ACE CS400, and when fitting, the undertray bolts needed some washers added to add some clearance, but even so, it would vibrate against it under load. The problem was solved with "percussive modification" of the undertray (ie, I flattened the part of it which was rubbing using a lump hammer).

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And if it's particularly Ace's, AFAIK it may rub also in overpipe portion, if worn engine mounts. Just hammering tray won't help in that case.

BTW, you should have read CEL code. "not able to use cruise control" CEL sounds very like what P0420 code of failed cat readiness check does. If one has aftermarket exhaust header installed, there is big chance for that to be the culprit. High chance for it to pop up sooner with catless header, but even using O2 sensor bungs/spacers on catless or having catted aftermarket header doesn't eliminate chance of it appearing. Hence why in most aftermarket ECU tunes P0420 related cat readiness checks get disabled. If you have ECU tuned, then i'd turn to tuner whichever did tune, so that to disable those cat readiness checks, how he should. (for example IIRC OFT forgot in early OFT OTS v4 stage2+ tunes to disable it. For that people posted manual fix in forum. If it's closed tune via ecutek, then one needs to turn to shop that made that tune).

And another source of noise might have been failed direct injector seals, if it's one of early twins with still very first stock ecu tunes, which dealership hadn't updated with newer one, "with transient ignition retard fix", and car got tracked (gear switches near redline). But less of a chance then rubbing of header / engine mounts as noise/rattling reason.

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What exhaust parts do you have fitted. I found that my OEM backbox resonated like crazy at that kind of RPM when had changed parts earlier in the system. The only way around it was to replace it.

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